Apparatus for burning liquid fuel



`uly 3, 1962 K. o. A. Bou ETAL 3,042,103

APPARATUS FORBURNING LIQUID FUEL 2 Sheets-Sheet 1 Filed July 28, 1959HP11?. Timm@ INVENTORS KARL OSKAR ARNE BOIJ 8 BERTIL KARL AXEL JOHANSSONATTORNEYS July 3, 1962 K. o. A. BOIJ ETAL 3,042,108

APPARATUS FOR BURNING LIQUID FUEL Filed July 28, 1959 2 Sheets-Sheet 2INVENTORS KARL OSKAR ARNE BOIJ 8x BERTIL KARL AXEL JOHANSSON ATTORNEYS3,042,108 APEPARATUS FR BURNKNG LEQUID FUEL Karl @saar Arne Boij, Agatan5, and Bertil Karl Axel .iohanssom Agatan 26, both of Tranas, SwedenFiled uly 2S, 1959, Ser. No. 830,139 Claims priority, application SwedenAug. 9, 1953 3 Qlaims. (Cl. 158-94) The present invention relates toapparatus for burning liquid fuel. More particularly the inventionrelates to apparatus of this kind adapted for burning spirit `and othervolatile fuel 'and comprising a fuel container having disposed therein afuel-absorptive tibrous mass and a wick in contact with this absorptivemass.

The invention has for its principal object to provide a combustionapparatus of the kind referred to which is improved in various respects.

An important object of the invention is to provide a combustionapparatus in which the flame will burn at :a substantially constantintensity as long as there remains any substantial quantity of liquidfuel within the absorptive mass.

Another `object of the invention is to produce a cornbustion apparatuswhich is spill-proof even for relatively large dimensions of the fuelcontainer and when using a fuel-absorptive charge capable of absorbing acomparatively large quantity of fuel per unit of its volume, and whichis at the same time explosion proof.

A further object of the invention is to provide a wick which is capableof being used for a long time without being destroyed, even if `thellame is in direct contact with the wick.

It is also an object of the invention to provide suitable means foradjusting the size of the flame, vand possibly also for preventing anyvolatilization of fuel from the wick when the combustion apparatus isextinguished.

Other objects and advantages of the invention will be set forth in thefollowing detailed description of a practical embodiment thereof inconjunction with the accompanying drawings, in which:

FIG. l is a vertical section through a combination cooking -and heatingstove to which the invention is applied, while FIGS. 2 and 3 show`horizontal cross-sections taken along the lines II-Il and III-HI,respectively, in FIG. l.

Referring to the drawings, numeral designates a closed cylindrical fuelcontainer having a diameter substantially greater than its height.Secured in a central opening in the top wall of the container is a tube11 for supporting a wick element designated generally by 12. Thesupporting tube 11 has its top portion projecting by a substantial`amount above the top wall of the container, while its lower portionprojects into the interior of the container 10 by an amountcorresponding `approximately to `one third of the container height.Inserted centrally in the supporting tube 11 is a narrow filling pipe 13which serves as an internal supporting tube for the `annul-arlycross-sectioned wick 12, is secured to the bottom wall of the container10, and is provided adjacent to the latter with a` number `of outletapertures 14 for the fuel. Obviously, fuel can only be filled into thecontainer 10 up to the bottom end of the supporting tube 11 since, afterthe fuel reaches this level, an air-pad will form preventing the spiritor other fuel from rising noticeably higher within the container.

The fuel container 10 is lilled up to the level coincident with thebottom end of the supporting tube 11 with a iibrous mass 15 which iscapable of absorbing land retaining a substantial amount of liquid fuelper unit volume of the mass. In the embodiment illustrated, theabsorptive mass 15 is assumed to consist of a punched-out an- Q n'lCCBMZMS Patented .iuly 3, 1962 nulus of mineral wool in which the fibreshave `a substantially horizontal orientation. The average thickness of`the libres of the yabsorption mass may suitably be 1.6-10*L1 to 2.4-104inches (0.004 to 0.006 millimeters). Generally, the iibre thickness ofthe labsorptive mass, or the degree of compaction thereof, respectively,will be so chosen as to form a system of capillaries which is capable ofabsorbing and retaining therein a maximum amount of liquid fuel.

The space above the absorptive mass 15 is iilled with la mass 16providing for comparatively large voids in rcommunication with eachother, such as wood wool or the like, so that 'the mass will only show alimited absorption and retaining capacity for liquid fuel. Yet, thepores of the filling mass 16 must be `suiiiciently small to exclude a'nydanger of ignition of explosive gases accumulating within the pores. Theportion of the container 10 receiving the filling 16 with wide pores orvoids is intended to serve as an auxiliary space for receiving suchliquid fuel `as cannot be retained by the absorptive mass l5 if the widecontainer 10 should be laid down on its side. Upon placing the container10 on its bottom again, the fuel received in the voids of the wood woolfilling will flow back into the absorptive mass to be absorbed by thelatter. Thus the apparatus shown in completely spillproof.

The wick 12 is made of synthetic fibres, for instance glass fibres ornylon fibre-s. The wick is passed downwardly, into close proximity withthe bottom of the container 10, through la hole in the absorptiveannulus 15, j

the Wick intimately contacting the walls of said hole so as to cause thesystem of capillaries in the wick to conimunicate with the system ofcapillaries in the -absorptive mass. In order to obtain an increasedarea of contact between the wick and the absorptive mass, the lowerportion 17 of the wick m-ay be enlarged in a substantially conical ormushroom-like fashion, as indicated in the drawing. The portion ofthewick 12 disposed within the supporting tube 11 and projecting upwardlyfrom the latter is surrounded by a sleeve 18 made of a porous and heatyresistant material, such as asbestos cloth, and passed over theasbestos sleeve 18 is a protective sleeve 19 of wire gauze or the like.

The glass fibres of the wick 12 are substantially thinner than those ofthe absorptive mass 15 and. may, for eX- ample, be of a averagethickness of no more than 0.-1-10"4 to 0.8- l0*4 inch (0.00l to 0.002millimeters). This means that, for substantially equal degrees ofcompaction of the wick and the absorptive mass, the capillaries of thewick, on an average, are considerably liner than the capillaries of theabsorptive mass. Therefore, the capillary forces in the wick will bemuch in excess of the capillary forces in the absorptive mass, wherebythe wick will remain saturated with fuel even after the major portion ofthe fuel originally received in the absorptive mass has been consumed.This, in its turn, will result in that the burner will operate with asubstantially constant flame almost until all the fuel hais beenconsumed, whereas, with substantally equal libre gauges, or`capillarities, of the wick and lthe absorptive mass, the concentrationof fuel in the wick would decrease at the same rate yas the `fuelconcentration in the absorptive mass, thus resulting in a continuouslydecreasing iiame.

To enable the iiame size to be adjusted, a tube 20 is provided which istelescoped over the supporting tube 11 so as to `be displaceablelengthwise along the latter by the aid of a control mechanism. In theembodiment shown, said mechanism comprises a U-shaped lever 21 which ispivotally connected to the container top wall at 22 and adapted tocooperate with a pair of lugs 23 projecting from the `adjusting tube210. At its end remote from the pivot 22 the lever 21 is formed with ahorizonaoaatos 3 tally extending slot 24 engaged by a crankpin 25 formedon a control crank 27 having a finger grip 26 and being rotatablymounted in a support Z8 projecting upward from the container top wall.As shown in the drawing, the crank 27 is displaceable endwise in thesupport 28 between an inner and an outer limit position.

As illustrated in the drawings, the apparatus for burning liquid fuel asdescribed is intended to serve as the source of heat of a combinationcooking and heating stove. The combustion -apparatus is disposed on thebottom wall of a cylindrical receptacle 30 within which the fuelcontainer is located in a centered position by four leaf springs 31secured to the inner wall surface of the receptacle. The springs 31 areformed with shoulders 32 having supported on them a plate 33 formedcentrally with a wide opening 34 through which the supporting tube 11for the wick projects upward by a small amount. The plate 33 protectsthe fuel container 1t? against radiation of heat from the flame anddirects the air for the combustion admitted below inwardly towards theannular clearance between the adjusting tube and the edge of theopening. Supported on the plate 33 is a arne diffuser 35 which isinvertedly cup-shaped and is formed in its bottom with a circumferentialrow of flame-egress apertures 36. In its top limit position theadjusting tube 2t) engages the cup-bottom whereby the flame isextinguished, after which any volatilization of fuel from the wick iseffectively prevented. The fiame diffuser cup 35 is maintained in acentered position by four vanes 37 secured to the plate 33, as byscrews, and on which a cooking vessel, a grill 38 or the like may beplaced. Provided in the lower portion of the side wall of the protectivereceptacle Sti-the latter being of a height sufficient to afford aWindshield for a cooking vessel placed on the vanes 37-are a pluralityof air-draught holes 39.

When the apparatus is to be used as a heating stove, a cover or cowl 49is placed on the receptacle 3f), said cowl having about its periphery acircumferential row of spaced outlet openings 41 for the gases ofcombustion and the heated air. For moving and handling the heatingstove, the cover 40 may be placed upside down, as indicated in brokenlines, thus reducing the height of the apparatus.

It should be understood, of course, that the invention is not limited tothe embodiment described in detail hereinbefore and as illustrated inthe drawings, since various modifications thereof are conceivable withinthe scope of the invention.

What we claim is:

l. In apparatus for burning volatile liquid, the combination comprisinga fuel container closed except for an opening in the top thereof, alayer of closely compacted and fuel absorptive fibrous material fillingsaid container from the bottom thereof to a predetermined highest fuellevel, a layer of relatively loosely compacted and porous material insaid container above said closely compacted absorptive material, each ofsaid layers being substantial in depth relative to the other, and saidporous material having therein voids and passages sufficiently large tokeep liquid fuel from being drawn thereinto by capillary action fromsaid absorptive fibrous material yet sufhciently small to inhibit anydangerous accumulation of explosive gases, a wick extending upwardlythrough said closely compacted absorptive material and said looselycompacted porous material and thence through said top opening, therebyto draw liquid fuel from the container by capillary action, and meanscircumscribing said top opening and extending from the top of saidcontainer between the wick and the loosely packed material to preventthe flow of liquid from the loosely packed i material through said topopening when the container is positioned on the side thereof.

2. In apparatus for burning volatile liquid, the combination comprisinga fuel container closed except for an opening in the top thereof adaptedto be occupied by a wick, a layer of closeiv compacted and fuelabsorptive fibrous material filling said container from the bottomthereof to a predetermined highest fuel level, a mass of materialfilling the space in said container between said predetermined highestfuel level and the top of said container, said last-mentioned mass ofmaterial including a layer of relatively loosely compacted and porousmaterial immediately .above and adjacent to said closely compactedabsorptive material and occupying at least a portion of the space insaid container between said predetermined highest fuel level and the topof said container, each of said layers being substantial in depthrelative to the other, and said porous material having therein voids andpassages sufficiently large to keep liquid fuel from being drawnthereinto by capillary action from said absorptive fibrous material yetsufficiently small to inhibit any dangerous accumulation of explosivegases, a wick occupying said opening and extending therethrough upwardlyfrom said absorptive and porous materials to the outside of thecontainer, thereby to draw liquid from the container by capillaryaction, and means circumscribing said top opening and extending from thetop of said container between the wick and the loosely packed materialto prevent the ow of liquid from the loosely packed material throughsaid top opening when the container is positioned on the side thereof.

3. in apparatus for burning volatile liquid, the combination comprisinga fuel container closed except for an opening in the top thereof adaptedto be occupied by a wick, a layer of closely compacted and fuelabsorptive fibrous material filling said container from the bottomthereof to a predetermined highest fuel level, a layer of relativelyloosely compacted and porous material filling said container from saidpredetermined highest fuel level to the top of said container, each ofsaid layers being substantial in depth relative to the other, and saidporous material having therein voids and passages sufficiently large tokeep liquid fuel from being drawn thereinto by capillary action fromsaid absorptive fibrous material yet sufficiently small to inhibit anydangerous accumulation of explosive gases, a wick occupying said openingand extending therethrough upwardly from said absorptive and porousmaterials to the outside of the container, thereby to draw liquid fromthe container by capillary action, and means encircling said top openingand extending from the top of said container between the wick and theloosely packed material to prevent the flow of liquid from the looselypacked material through said top opening when the container ispositioned on the side thereof.

References Cited in the file of this patent UNITED STATES PATENTS395,730 Anderson Ian. 8, 1889 439,560 Reinhold Oct. 28, 1890 564,991Gregory Aug. 4, 1896 911,622 Smith Feb. 9, 1909 1,638,498 McNutt Aug. 9,1927 2,086,639 Reese July 13, 1937 2,441,242 Harkins May 1l, 19482,879,837 Downs Mar. 31, 1959 FOREGN PATENTS 18,415 Great Britain 1891infr; .5mm

